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Re: [PATCH perf/urgent] perf tools: Fix the code to strip command name

Hi Jiri,

On 04/20/2017 06:24 PM, Jiri Olsa wrote:
Recent commit broke command name strip in perf_event__get_comm_ids
function. It replaced left to right search for '\n' with rtrim,
which actually does right to left search. It occasionally caught
earlier '\n' and kept trash in the command name.

Sorry for my commit that have failings.

Could I know the command name in the above case ?
The command name can have two '\n' ?


Keeping the ltrim, but moving back the left to right '\n' search
instead of the rtrim.

Fixes: bdd97ca63faa ("perf tools: Refactor the code to strip command name with {l,r}trim()")
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Taeung Song <treeze.taeung@xxxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-51mt8hxaig74zlu42s3rv0i7@xxxxxxxxxxxxxx
 tools/perf/util/event.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index cf457ef534da..1a9164a816d9 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -138,8 +138,15 @@ static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len,
 	ppids = strstr(bf, "PPid:");

 	if (name) {
+		char *nl;
 		name += 5;  /* strlen("Name:") */
-		name = rtrim(ltrim(name));
+		name = ltrim(name);
+		nl = strchr(name, '\n');
+		if (nl)
+			*nl = '\0';
 		size = strlen(name);
 		if (size >= len)
 			size = len - 1;